China's Sun Yang set another world record on the final night of swimming at the Olympic pool, sprinting to the finish of the sport's most grueling race to crush the mark he already held in the 1,500-meter freestyle Saturday. On a night when Michael Phelps was set to swim the last race of his brilliant career, Sun put his stamp on the London Games with a stunning time of 14 minutes, 31.02 seconds, beating the mark he set at last year's world championships by 3.12 seconds and setting the eighth world record of the Olympics. Sun captured his second gold of the meet, adding to a gold in the 200 free. He also tied for the silver in the 200 free, and was part of the bronze medal-winning team in the 4x200 free relay. For a brief moment, it appeared Sun might not even get a chance to swim the race. Apparently hearing a noise in the crowd, he dived into the water before the starter's gun, while everyone else remained on the blocks. Yang glanced at the starter with a confused look, got back out of the pool and waited to see if he would be disqualified. "I could not hear the judge because there was noise in the venue," Sun said through an interpreter. "I thought I was going to be disqualified. I have done well because I was in very good shape. I really wanted this gold medal." But the starter allowed him to go, which essentially decided the gold medal. No one else was close to Sun, who was going faster at the end than he was at the beginning, leaving everyone behind. After looking at his time and catching his breath, Sun was overcome with emotion. He climbed on the lane rope, splashed the water, pointed toward a group of supporters waiving a Chinese flag, and broke down in tears. Canada's Ryan Cochrane took the silver in 14:39.63, while defending Olympic champion Ous Mellouli of Tunisia settled for bronze in 14:40.31. Mellouli will get another chance for gold when he races in the 10-kilometer open water event at Hyde Park. In a night featuring the long and short of swimming, Ranomi Kromowidjojo of the Netherlands won the women's 50 freestyle to complete a sweep of the sprints. Having already won the 100 free, Kromowidjojo clocked an Olympic-record 24.05 in the furious, one-lap dash. Defending champion Britta Steffen of Germany went 24.06 in Beijing four years ago in a now-banned bodysuit. Aliaksandra Herasimenia of Belarus touched in 24.28 to take the silver medal and another Dutchwoman, Marleen Veldhuis, finished in 24.39 to take bronze. Steffen, who swept the sprints in Beijing, finished fourth, while home favorite Francesca Halsall of Britain was fifth and 34-year-old Therese Alshammar of Sweden was sixth in her fifth Olympics. (For more sports news and updates, follow Ahram Online Sports on Twitter at @AO Sports and on Facebook at AhramOnlineSports)